1. Field of the Invention
The present invention relates to a bat, and particularly relates to an extendable bat.
2. Description of the Related Art
With reference to FIGS. 8-10, a conventional bat has a covering member (50), a tubular core (60), a handle (70), an adjusting device (80), and a cap (65).
The covering member (50) made of foam plastic materials is mounted around the tubular core (60) and has a front end (51) and a rear end (52). The front end (51) is equipped with the cap (65). The tubular core (60) is hollow and has a front end (61) and a rear end (62). An annular slot (63) is defined in an outer periphery of the tubular core near the rear end (62), and a rail (64) is axially formed an inner wall of the tubular core (60). The handle (70) has a front end (71) and a rear end (72). The handle (70) is adjustably mounted in the tubular core (60) to adjust the length of the bat. The adjusting device (80) is composed of a first locking member (81) formed in the front end (71) and a second locking member (85) slidably mounted in the tubular core (60). The first locking member (81) has a stop ridge (82), and a taper head (83) with outer screw thread extending from the stop ridge (82). The second locking member (85) has a split sleeve (86), an inner thread (87) defined in the split sleeve (86), a channel (88) defined axially in  an outer periphery of the split sleeve (86) to engage with the rail (64), and a slit (89) is defined in the split sleeve (86) axially.
To adjust the length of the conventional bat, the handle (70) is rotated and the first locking member (81) is rotated with the handle. Then, the taper head (83) is retracted from the second locking member (85), such that the handle (70) can be moved outward or inward the tubular core (60) so as to adjust the length of the bat. When the stop ridge (82) engages with the annular slot (63), the handle will not be moved anymore to achieve the longest length of the bat. In addition, with the arrangement of the slit (89), a resilient force is provided to the split sleeve (86). Accordingly, the taper head (83) of the first locking member (81) is securely engaged with the split sleeve (86) of the second locking member (85) to hold the handle (70) in place relative to the tubular core (60).
However, to form the inner thread (87) inside the split sleeve (86) is difficult, and the split sleeve (86) with the taper head (83) easily disengages from each other. In addition, when the handle (70) is completely held inside the tubular core (60), the cap (65) will be pushed by the handle (70) to be escaped from the covering member (50).
Therefore, the invention provides an extendable bat to mitigate or obviate the aforementioned problems.